This guy is not bad, as long as you know how to defeat him. When he puts up a barrier, use the minion of that same colour to attack him and his barrier will break, causing him to fall onto the floor. Run in and smack him with your weapon until he pushes you away. Dodge his sweeping attacks and his whirlwind (move your minions to the side areas or the entry). He'll send waves of evil minions at you as well, so kill them too. Just keep up this strategy until he falls, it won't take long. Enjoy your ending!